1. Field of the Invention
This invention relates to a laser surveying system capable of measuring reference points necessary for executing building or civil engineering work by use of a a laser and marking the reference points with laser spot pattern on the basis of the measuring results.
2. Description of the Prior Art
For surveying, measurement and maintenance of all sorts of constructions such as buildings, roads and tunnels, there have been widely used various types of handy laser surveying systems capable of providing highly accurate measurement. Not infrequently there are times when measuring reference points on the construction as noted above are desired to be marked on the basis of structural data obtained as the result of the measurement. In a case of marking a structure such as a working pit face of a tunnel, a method is commonly used in which reference points are manually marked one by one with paint while projecting one laser spot on the object structure to indicate one of a reference points. In particular, the use of the visible laser is available in tunneling work which is carried out in a dark place.
For example, in the so-called "NATM" tunneling method, a hard base rock in the working pit face of a tunnel is blasted with explosives. In the blasting tunneling work, explosive charging holes are previously bored in the working pit face at the geodetically specified points predetermined in accordance with the design of the tunnel construction which are strictly determined in advance. Although the specified points at which explosive charging holes are bored in the working pit face of the tunnel can be automatically established by use of a computer, the work of marking the design points for boring the explosive charging holes has been manually carried out, and automation of marking the working pit face in the tunneling construction cannot yet be accomplished.
A laser projector used in a laser marking method for optically determining a plurality of surveying or working reference points on the working face of the object structure to be marked radiates one laser beam to form one laser spot on the working face. Therefore, the aforesaid reference points were indicated by the laser spot one by one to be marked manually with paint. The manual marking work with paint is continued for other reference points in order, but turns out to be a very troublesome chore.
To be more specific, when the explosive charging holes are bored in the working pit face in the tunneling work, one of the portions to be bored on the working pit face is optically indicated by the laser spot issued from the laser projector and marked manually with paint. Upon completion of marking one portion with paint, the laser projector is moved so as to form the laser spot on another objective portion in which the hole is bored in the working face. The objective portion is marked manually with paint while being indicated by the laser spot in the same manner. This marking work is repeated, but cannot be automatically executed and is much harder and more time-consuming than might be expected.
Furthermore, the conventional laser marking device including the laser projector is disadvantageous in that the operation rate thereof is low. That is to say, the laser marking device of this type is used only when the marking is performed, but is out of operation when other measurement or work such as timbering is executed. Thus, the conventional laser marking device can not be used efficiently. For instance, in tunneling work, another measuring device is necessary for making a land survey or measuring displacement of a different object structure when performing the optical marking on the working face by use of the laser projector. Thus, the conventional laser marking device has been used only inefficiently.